a: \(P=\dfrac{x\sqrt{2}-\sqrt{x}+\sqrt{2x}-1+2x+\sqrt{2x}+x\sqrt{2}+\sqrt{x}-2x+1}{2x-1}:B\)
\(=\dfrac{2x\sqrt{2}+2\sqrt{2x}}{2x-1}:\dfrac{2x-1+x\sqrt{2}-\sqrt{x}+\sqrt{2x}-1-2x-\sqrt{2x}-x\sqrt{2}-\sqrt{x}}{2x-1}\)
\(=\dfrac{2\sqrt{2x}\left(\sqrt{x}+1\right)}{2x-1}\cdot\dfrac{2x-1}{-2-2\sqrt{x}}\)
\(=\dfrac{2\sqrt{2x}\left(\sqrt{x}+1\right)}{-2\left(\sqrt{x}+1\right)}=-\sqrt{2x}\)
b: Khi x=1/2(3+2căn2) thì \(P=-\sqrt{2\cdot\dfrac{1}{2}\left(3+2\sqrt{2}\right)}=-\sqrt{2}-1\)
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